Wraiths are a weird phenomenon, rare enough that the majority of the MythosThe Mythos refers to six of the Seven Peoples of the Earth, ... has no idea they exist.

For the record, they are not ghosts. GhostsGhosts are one of the few remaining members of the Dream to ... are echoes of people who’ve died. Wraiths, on the other hand, are pieces of beings who have died and who can never be whole, for most of their essential selves has been destroyed.

HadesHades is one of the ancient, strange beings known as gods.... – Death – cares for these beings, though the details are unclear. He’s lent a few to NotteName meaning: Night (Italian - he picked that one)Other na... as servants, which can be deeply startling for visitors.

The description:

A white thing—a puff, a phantom, a see-through blobby shape like a pillowcase underwater—flew through the wall and between them, bringing with it a cold wind and wearing an impossibly solid red bowtie near its top. […] It had a shape, of sorts—curvy and blobby and really not humanoid. There were no limbs. The red bow-tie indicated the possibility of a head, but there was no face; above the tie, the blob tapered, ending in a sort of empty-windsock sag.